• Preventive Nutrition and Food Science
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• 제2권1호
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• pp.66-70
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• 1997

A mixed-culture of Gluconobacter suboxydans IFO 3172 and Saccharomyces uvarum IFO 0751 was per-formed in a synthetic medium. the optimal inculum ratio of G. suboydans and S. uvarum for mixed-culture fermentation was 150:1. The optimum pH, incubation temperature and aeration rate for mixed-culture fer- mentation were 5.0, 3$0^{\circ}C$ and 2.25vvm, reapectively. As a result of batch pure-and mixed-culture fer-mentation, specific growth rate in pure-culture of both strain was lower than that in mixed-culture. The yield of cell mass from S. uvarum exclusively decreased. The growth rate of the mixed-culture was very similar to the pure-culture in the begining of culture, but it has been decreased after 16hrs. In the mean time, S. uvarum in mixed-culture fermentation could grow due to fructose converted, but it could not row in pure-culture fermentation. Thus, the relationship was a sort of commensalism. The kinetic parameters cal-culated through steady-state results during continuous fermentations are as follows :{TEX}$$\mu$_{max1}${/TEX}=0.118({TEX}$h^{-1}${/TEX}), {TEX}$Ks_{1}${/TEX}=0.330(g/L),:{TEX}$$\mu$_{max2}${/TEX}=0.162({TEX}$h^{-1}${/TEX}), {TEX}$Ks_{2}${/TEX}=0.038(g/L). The yield of bacterial cell mass relatively constant, but yield of yest cell mass was gradually decreased.

• 한국식품영양학회지
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• 제11권6호
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• pp.683-688
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• 1998

This study was conducted to develop optimal composition of flour brew in order to economically utilize flour brew inoculated by lactic acid bacteria as a starter(mother sponge) in bread-making. Two flour brews were prepared ; one with flour and water, the other with flour, water and NaCl. Various nutrients were added to both flour brews and Lactobacilli deMan Rogosa and Sharpe (MRS) broth to investigate the effect of them on growth and activities of Streptococcus thermophilus, Lactobacillus brevis and their mixed culture in flour brews to be tested with incubation at 37$^{\circ}C$. The growth of Streptococcus thermophilus, Lactobacillus brevis and their mixed culture was stimulated by addition of NaCl with 0.85% concentratin and more by mixed culture than by single lactic acid bacteria, resulting in 3 hrs reduction in cultivation and more by mixed culture than by single lactic acid bacteria, resulting in 3 hrs reduction in cultivation time. the addition of 3% glucose to flour brew with NaCl was observed to enhance acid productioni by mixed culture. Yeast extract greatly affected growth and activities of mixed culture of lactic acid bacteria in flour brew with NaCl and its optimum level of this additive in flour brew with NaCl was approximately 1.0%. The optimal composition of flour brew for mixed culture of lactic acid bacteria was suggested as follows; flour 100g, water 300g, NaCl 3.46g, glucose 12.48g, yeast extract 3.46g.

• 한국미생물·생명공학회지
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• 제27권1호
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• pp.46-53
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• 1999

The purpose of this study was to optimize the conditions of continuous mixed culture of C.butyricum and R. spaeroides K-7, which were able to produce hydrogen using biomass-dreived substrate. To investigate the possibility of continuous culture, semi-continuous culture was carried out for 20 days. In semi-continuous culture using the reactor system, the replacement rate of fresh medium was 30% of total medium volume for the highest hydrogen evolution. In continuous culture, the optimum dilution rate was determined to be 0.05$h^{-1}$. The continuous culture produced 3.1 times as compared with the hydrogen on batch culture. On the other hand, the continuous mixed culture produced 1.3~2.1 times as much as hydrogen of the continuous monoculture of C. butyricum. When 10g of glucose in the media (1l) was supplied as a carbon source on continuous culture, mixed culture of C. butyricum and R. sphaeroides K-7 increased hydrogen evolution rate. Because considerable amount of glutamate was contained in waste water of glutamate fermentation, utilization of glutamate was examined in mixed culture. As a result of examination, production of hydorgen was slightly inhibited by high concentration of glutamate, more than 20mM, on continuous monoculture of R. sphaeroides K-7. On the other hand, both on continuous monoculture of C. butyricum and on mixed culture of C. butyricum and R. sphaeroides K-7, production of hydrogen was not inhibited by high concentration of glutamate such as 100mM. Hence this suggests that high concentration of waste water can be used as good substrate for hydrogen production on monoculture of C. butyricum and mixed culture of C. butyricum and R. sphaeroides K-7.

• 동아시아식생활학회지
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• 제27권3호
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• pp.348-363
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• 2017

We analyzed the mixed culture characteristics of isolated brewing fungi obtained from Korean traditional nuruk for their development as fermentation starters. In a previous study, we selected appropriate fungi strains based on their large fungi bodies and strong enzyme activities. These fungi strains were mixed cultured under various combination of ratios, pHs and temperatures. As a result, total acidities of R. delemar mixed culture media were higher than those of A. oryzae cultured at $20^{\circ}C$ and $37^{\circ}C$. The pHs of A. luchuensis 34-1 and A. oryzae 37-7 as well as R. delemar 58-8 and A. oryzae 37-7 mixed culture media gradually increased with the culture period. On the contrary, total acidities of the mixed culture media gradually decreased. ${\alpha}-Amylase$ activities of R. delemar 26-4 and R. oryzae 82-7 mixed culture media were strong at $20^{\circ}C$ and pH 4, glucoamylase activities of R. delemar 58-8 and A. oryzae 37-7 were strong at $37^{\circ}C$, pH 3 and 1:2 ratio, and acidic protease activities of R. delemar 26-4 and A. oryzae 78-5 were strong at $20^{\circ}C$, pH 4 and 1:4 ratio. This study provides the optimal mixed culture conditions for fermentation starters based on changes in pH and total acidity, favorable enzyme activities, and fungi varieties.

• 한국식품영양과학회지
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• 제27권6호
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• pp.1059-1064
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• 1998

Fermented beverage using lactic acid bacteria isolated from kimchi was investigated. Lactic acid bacteria KL 1, KD 6, KL 4 strains from kimchi, or obtained Lactobacillus acidophilus, Lactobacillus plantarum, Leuconostoc mesenteroides with and without yeast(Saccharomyces cerevisiae) were inoculated in fruit vegetable juice for single and mixed culture fermentation. During the fermentation by bacterial strain and yeast for 1~3 days at 30oC, various fermentation behaviors were observed. The growth rate of mixed culture of KL 1 and yeast was higher than that of single culture by KL 1 alone during the fermentation. The amount of organic acid produced by the mixed culture fermentation of KL 1 and yeast was 0.82%(3 day) or 0.58%(1 day) and with the final pH of 3.3(3 day) or 4.2(1 day). These mixed culture systems of isolated strains or other bacterial strains had almost similar results of growth rate and acid production. Among several bacterial strains, KL 1 was suitable for the mixed culture fermentation with yeast in terms of desirable fermentation behavior and organoleptical quality. The selected strain, KL 1 was identified as Leuconostoc spp. through the series of tests on carbohydrate fermentation and biochemical characteristics.

• 생명과학회지
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• 제6권1호
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• pp.27-33
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• 1996

치즈숙성과정 중에서 Lactococcus lactis subsp. cremoris KH (lac$^{+}$ prt$^{+}$ ) and KHA (lac$^{-}$ prt$^{-}$ )의 혼합균에 의하여 일어나는 반응을 연구하였다. 혼합균의 성장 특징은 한쪽 균의 도움에 의하여 같이 성장하는 특징을 나타내었으며, 이 혼합균의 단백질분해효소의 양은 충분히 적었다. 이 결과로부터 치즈숙성과정 중에 홈합균의 균밀도가 높게 유지되더라도, 이 혼합균에 의하여 생성되는 쓴 맛의 생성량은 큰 문제가 되지 않는다는 결론을 얻을 수 있다. 그러므로, 치즈 숙성 과정을 촉진시키는데 있어서 KHA1의 혼합균은 좋은 치즈스타터균의 하나라고 할 수 있다.

• 미생물학회지
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• 제19권1호
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• pp.14-22
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• 1981

Protein content of cellulosic wastes, such as spent grain, hop bark, spent rye, rice straw, rice hull, saw dust and used newspaper, was increased by a mixed culture of C. utilis wastes having 66-75% moisture. Among the fungal strains tested. A.phoenicis KU175 was the most powerful to increase the protein content of A. phoenicis during the mixed culture with C. utilis in the CMC medium reached at the peak for one day culture after inoculation of the both strains at the same time, while it reached at peark from the beginning of the mixed culture, when A. phoenicis was inocultated for 12-24hours prior to the inoculation of C.utilis. To increase the protein content of the cellulosic wastes by the mixed culture of C.utilis and A.phoenicis, the inoculation of both strains at the same time was more effective than the preinoculation of A. phoenicis for 6-24 hours. Content of crude cellulose in the used newspaper, saw dust and spent grain was high relatively, and the lignin content of spent grain, spent rye, and rice strew was reduced more than half by the treatment of 2% NaOH. However, effect of alkali treatment of increase the protein content of the cellulosic wastes was not prominent in the case of mixed culture. Protein content of the cellulosic wastes was increased prominently by the mixed culture of C.utilis and A.phoenicis in semi-solid substrate, compared with the single culture of C. utilis, although the latter increased the protein content of cellulosic wastes considerably. The effect of mixed culture of C. utilis and A. phoenicis increased 4-fold the protein content of spent grain, and more than doubled crude protein in hop bark and rice straw.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
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• pp.136-139
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• 2001

In this study, we have examined potential degradation of MTBE (methy1 tert-butyl ether) by pure culture ENV425 and mixed culture isolated from gasoline contaminated soil using n-butane as the sources of carbon and energy. The results described in this study suggest that MTBE is degraded cometabolically by ENV425 and mixed culture grown n-butane, and the disappearance of TBA after complete degradation of MTBE suggest the further degradation of TBA. Butane and MTBE degradation was completely inhibited by acetylene, which indicated that both substrates were degraded by butane-utilizing bacteria. MTBE was degraded ENV425 and mixed culture grown n-butane, and TBA (tert-butyl alcohol) was produced as product of MTBE oxidation. TBA production was accounted 54.7% and 58.6% for MTBE oxidation by ENV425 and mixed culture, respectively. The observed maximal transformation yield (T$_{y}$) were 44.7 and 34.0 (nmol MTRE degraded/$\mu$mol n-butane Utilized) by ENV425 and mixed culture, respectively.y.

• 한국식품영양과학회지
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• 제27권6호
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• pp.1065-1070
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• 1998

Lactic acid bacteria KL 1, KD 6, KL 4 strains isolated from kimchi, or obtained Lactobacillus acidophilus, Lactobacillus plantarum, Leuconostoc mesenteroides with and without yeast(Saccharomyces cerevisiae) were inoculated in fruit vegetable juice for mixed culture fermentation 3 days at 3$0^{\circ}C$, and then their chemical changes were studied during fermentation. The amount of organic acid produced by the mixed culture fermentation of KL 1 and yeast was 0.82%(3 days) or 0.58%(1 day) and with the final pH of 3.3(3 days) or 4.2(1 day). These mixed culture systems of isolated strains or other bacterial strains had almost similar results of growth rate and acid production. The contents of vitamin C and carotene were retained and stabilized as 70~80% level of their initial values after 24 hrs fermentation. And also ethanol was produced as of the range in 9.6mg%(W/V) by the mixed culture fermentation of KL 1 and yeast, however, the content of ethanol in single culture fermentation by KL 1 strain was much lower than that of mixed culture. The major components of organic acids in fermented juice by mixed culture were considered as malic(26.0%), lactic(49.9%), succinic and citric acid, whereas these of unfermented juice were malic(53.2%), citric and other acids. On other hand, reducing sugar was decreased from 18.3mg/ml in fresh juice to about 12mg/ml in juice by mixed culture fermentation. Concentrations of fructose, glucose and sucrose were also greatly reduced in fermented juice.

• 한국식품위생안전성학회지
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• 제16권3호
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• pp.206-211
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• 2001

곰팡이독소 생성균과 비생성균의 혼합배양이 곰팡이독소 생성에 미치는 영향을 조사하기 위하여 Aspergillus flavus (aflatoxin 생성균), Aspergillus nigey(비생성균) 그리고 Penicillium griseofulvum (patulin 생성균)을 5 ml의 SLS 배지에서 15일동안 단독 혹은 혼합배양하였다. Afatoxin의 생성능의 측정은 직접경쟁 ELISA법으로, patulin은 HPLC 법으로 생성능을 측정하였으며, 균의 생육도, pH 그리고 산생성량을 상법에 따라 측정하였다. 그 결과 혼합배양은 전체적으로 균의 생육도를 크게 저하시키지 않은 반면, 산의 생성증가로 pH의 감소를 보였다. Aflatoxin은 12일간의 단독배양시 145 $\mu\textrm{g}$/ml이 생성되었으나 혼합배양으로 93%이상이 감소되어 10.26$\mu\textrm{g}$/ml을 생성하였다. Patulin의 경우도 혼합배양으로 단독배양시의 77.82$\mu\textrm{g}$/ml에 비하여 69.5%가 감소된 23.72$\mu\textrm{g}$/ml 수준을 나타내었다.